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Nordic cooperation on subalpine fir

Date: 2016.09.05

Grafting of plus-trees of Abies lasiocarpa for indoor seed production in Iceland. Photo:Brynjar Skulason

One aim of the Ph.D project is to gather the overall existing information on the differences between and within the different provenances of subalpine fir (Abies lasiocarpa) with regards to mortality, growth, tree properties, resistance to aphids and fungi, post-harvest quality, growth rhythm and not least how different factors and their interaction affect Christmas tree quality.

Choice of material

The results of the Ph.D. project will build on all the measurements that have been carried out so far in three Danish and one Icelandic field trial.

It is expected that the results will provide good basis for a sensible choice of quality material that can be used to establish seed orchards and further processing of subalpine fir for Christmas trees in Denmark and Iceland. The refined material (quality material) is expected to have enhanced Christmas tree characteristics and have a greater resistance to damage from aphids, fungus and more frost resistant.

Joint Nordic research project

In early summer 1999, 27 different provenances of subalpine fir were planted in 3 field trials in Denmark, Iceland and Norway. The trials were a part of a joint Nordic research project. The selected provenances came from the natural range of subalpine fir, extending from Yukon, 61 ° N in the north to Arizona, 34 ° N in the south. The field trials were measured after three years of growth (in autumn 2002). Survival, growth and desirable properties to Christmas trees were registered in all three countries and published (2).

Although the results from the first three-year trial period gave some information, it was not sufficient to determine the final yield of Christmas trees and differences between provenances. Therefore, survival, growth and tree quality was subsequently measured and assessed again in the Icelandic field trials in 2006 and 2011.

Corkbark fir (Abies lasiocarpa var. arizonica) – the blue type of subalpine fir. Photo: Brynjar Skulason

Tests on pests essential for ranking

Provenance ranking compared with the measurements in 2002 had hardly changed and there was no evidence of fungal or damage caused by balsam woolly aphid . The Danish field trials have been measured and evaluated in the years 2007, 2008 and 2011 and the main results are published in various publications (1,3,4,5,6). As well as measuring the growth and important properties for Christmas trees, damages by aphid and fungi were also assessed and recorded. These pests have clearly influenced provenance ranking with regards to Christmas tree quality after the year 2007 (6).

Data from the Danish material is therefore an opportunity to assess the adaptability of different provenances of subalpine fir in relation to climate, aphids and fungi, as well as any interactions between them. In addition to the previously mentioned documents twigs were also gathered from all 27 provenances in the field experiments to assess the provenance post-harvest quality.

Freeze tests and growth rythm

In the Icelandic studies twigs were collected to perform freeze test. Twigs were collected in spring and autumn and frozen at various temperatures to get a better understanding of the growth rhythm of individuals and provenances. Knowing the growth rhythm is important to get a better understanding of the causes and contexts that may be related to an increased rate of death, injury, poor growth and other growth related attributes recorded in field trials.

Text: Brynjar Skulason. Brynjar is a PhD student at the Faculty of science, University of Copenhagen. In his studies he investigates the adaptability of different provenances of subalpine fir (Abies lasiocarpa) for Danish and Icelandic climate conditions.

References:

Bjergager, C., Hansen, O.K. & Nielsen, U.B. 2009: Dansk forsøg med provenienser af Abies lasiocarpa. Nåledrys 67: 15-20.
Hansen, O. K., Nielsen, U. B., Edvarsen, Ø.M., Skulason, B. & Skage, J.-O. 2004: Nordic Provenance Trials with Abies lasiocarpa and Abies lasiocarpa var. arizonica: Three-year Results. Scandinavian Journal of Forest Research 19: 12-126.
Nielsen, U.B., Hansen, O.K. & Bjergager, C. 2011: Betydende faktorer for juletræsegnethed i Abies lasiocarpa. Videnblade Pyntegrønt nr. 3.4-23, Skov og Landskab, 2 pp.
Nielsen, U.B., Hansen, O.K. & Bjergager, C. 2011: Lokalitetsforskelle i udbytte af Abies lasiocarpa. Videnblade Pyntegrønt nr. 3.4-24, Skov og Landskab, 2 pp.
Nielsen, U.B., Hansen, O.K. & Bjergager, C. 2011: Proveniensanbefalinger for Abies lasiocarpa. Videnblade Pyntegrønt nr. 3.4-25, Skov og Landskab, 2 pp.
Nielsen, U.B. & Hansen, O.K. 2011: Opdatering af proveniensvalget i lasiocarpa. Nåledrys 77: 10-13.